1. Field of the Invention
This invention pertains to medical devices in general, and in particular, to a device for rapid, closed-chest cardiopulmonary cannulation through punctures in the femoral veins and arteries.
2. Description of Related Art
Life-threatening medical emergencies frequently encountered in typical hospital emergency rooms include myocardial infarction, cardiogenic shock, congestive heart failure, cardiac arrest, pulmonary embolus, pulmonary edema, profound accidental hypothermia, smoke inhalation, drowning and drug overdose. In any one of the foregoing situations, fast, competent cardiopulmonary bypass and support of the patient can often spell the difference between life and death.
In U.S. Pat. No. 4,540,399 to Litzie et al, a simplified, closed, extracorporeal heart-lung bypass system is described suitable for use in emergency situations.
Central to the utilization of such a system is the ability quickly to establish the bypass circuit between the patient and the machine, which in turn, requires a rapid access to venous and arterial blood. This can be achieved without opening the patient's chest by cannulation of the patient's cardiopulmonary system through the femoral veins and arteries, respectively, through incisions in the patient's upper thighs, provided suitable cannulae are at hand.
Use of cannulae as a means of draining or perfusing a cavity within the body is well known.
Amrine, in U.S. Pat. No. 4,129,129, discloses a venous return catheter, including an obturator used to control the flow of blood therethrough adapted to interconnect a patient's heart to a life support machine during open heart surgery, as well as the openchest surgical technique utilized for its placement.
In U.S. Pat. No. 4,033,331, Guss et al describe a cardiac catheter having a preformed distal end and a pair of parallel lumen. In one of the lumen a contour wire used to straighten or contour the catheter during or after insertion so that the outlet of the other lumen may be properly disposed to, e.g., inject an angiographic dye. Also discussed are a number of related devices and their method of use, all of which entail a time-consuming "cut down" procedure in which the vein or artery used to access the target region, including the femoral artery, is surgically prepared to receive the device.
Although these and other similar prior devices all represent contributions to the art, none are suitable for rapid cardiopulmonary bypass through the femoral veins or arteries for at least the following reasons: Those which are easily introduced through, e.g., a puncture created by a hypodermic needle, are too small to pass an adequate blood flow for successful bypass. Thus, they are suitable only for sampling or dye injection. Those having sufficient luminal area to transport an adequate blood flow are either so thin-walled as to rely entirely on the venous side to avoid kinking or collapse, as would be occasioned by the suctional forces associated with a positive extraction pump, or are so thick-walled as to result in a conduit that is both stiff and large in overall diameter. Such a conduit, if it can be inserted at all into a body vessel, requires a substantially long incision in the intended vessel for insertion, with a concomitant consumption of valuable time in surgical preparation and execution.
It is therefore an object of the present invention to provide a vascular cannula which is suitable for rapid, closed-chest, cardiopulmonary bypass through the femoral veins and arteries, and which is sufficiently smooth, flexible, thin-walled and narrow as to permit its rapid insertion through punctures created in those vessels by a hypodermic needle.
Yet another object of the present invention is to provide a cannula which posesses both sufficient luminal area to provide adequate hemodynamic flow of at least 2.0 liters/minute per square meter of body surface area during bypass, and an unsupported hoop strength sufficient to resist collapse from typical suctional and vasoconstrictive forces.
It is another object of the present invention to provide an associated, disposable means for introducing such a cannula which, when used in conjunction with a guide wire, is capable of inserting and guiding the cannula through the puncture and longitudinally through the vessel, for locating the distal end of the cannula within a predetermined venous or arterial region, and for supporting and obturating the cannular during insertion thereof.
It is yet another object of the present invention to provide a combination of the foregoing elements in a device which can be fabricated inexpensively and supplied to hospitals complete in a prepackaged, sterile unit ready for use.
It is still another object of the present invention to provide a method for using such a device in a cardiopulmonary bypass procedure.